PRINCIPLE n.
Any original inherent constituent which characterizes a substance, or gives it its essential properties, and which can usually be separated by analysis; -- applied especially to drugs, plant extracts, etc. Cathartine is the bitter, purgative principle of senna. Gregory. Bitter principle, Principle of contradiction, etc…
REPULSION n.
The power, either inherent or due to some physical action, by which bodies, or the particles of bodies, are made to recede from each other, or to resist each other's nearer approach; as, molecular repulsion; electrical repulsion.